﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Serialization;

namespace FileStorage.MetaData.Helper
{
    //
    // as it appears a 'default' Dictionary is not serializble,
    // this class extends the basic Dictionary and adds xml serialization support
    // entirely copied from
    // http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx
    //
    [XmlRoot("dictionary")]
    public class SerializableDictionary<TKey, TValue>
        : Dictionary<TKey, TValue>, IXmlSerializable
    {
        #region IXmlSerializable Members
        public System.Xml.Schema.XmlSchema GetSchema()
        {
            return null;
        }
 
        public void ReadXml(System.Xml.XmlReader reader)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));
 
            bool wasEmpty = reader.IsEmptyElement;
            reader.Read();
 
            if (wasEmpty)
                return;
 
            while (reader.NodeType != System.Xml.XmlNodeType.EndElement)
            {
                reader.ReadStartElement("item");
 
                reader.ReadStartElement("key");
                TKey key = (TKey)keySerializer.Deserialize(reader);
                reader.ReadEndElement();
 
                reader.ReadStartElement("value");
                TValue value = (TValue)valueSerializer.Deserialize(reader);
                reader.ReadEndElement();
 
                this.Add(key, value);
 
                reader.ReadEndElement();
                reader.MoveToContent();
            }
            reader.ReadEndElement();
        }
 
        public void WriteXml(System.Xml.XmlWriter writer)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));
 
            foreach (TKey key in this.Keys)
            {
                writer.WriteStartElement("item");
 
                writer.WriteStartElement("key");
                keySerializer.Serialize(writer, key);
                writer.WriteEndElement();
 
                writer.WriteStartElement("value");
                TValue value = this[key];
                valueSerializer.Serialize(writer, value);
                writer.WriteEndElement();
 
                writer.WriteEndElement();
            }
        }
        #endregion
    }
}